Submission

Score: 100

User: samsenpisardmoo

Problemset: อนุกรม

Language: cpp

Time: 0.003 second

Submitted On: 2025-09-30 20:34:57

#include <stdio.h>

long long fib(int n) 
{
    if (n <= 2) return 1;

    long long a = 1, b = 1, c;
    for (int i = 3; i <= n; i++) 
    {
        c = a + b;
        a = b;
        b = c;
    }
    return b;
}

int main() 
{
    int n;
    scanf("%d", &n);

    long long ans = fib(n);
    printf("%lld\n", ans);

    return 0;
}